isspace()

Prototype: int isspace(int ch);
Header File: ctype.h (C) or cctype (C++)
Explanation: Isspace does exactly what is sounds like, checks if the ASCII
value passed in is that of a space key (such as tab, space, newline, etc). It
returns non-zero for true, and zero for false.

//Example reads in a character and checks if it is a type of space
#include <iostream>
#include <cctype>
using namespace std;
int main()
{
char x;
cin>>x;
if(isspace(x))
{
cout<<"It's a space";
}
else
{
cout<<"It's not a space;
}
}